Piston for two-cycle engines



May 29, 1934. B. G. PARSONS PISTON-FOR TWO-CYCLE ENGINES Filed June 6, 1929 Patented May 29, 1934 PISTON FOR TWO-CYCLE ENGINES Ben G. Parsons, Houston, Tex., assignor to Hurricane Motor Company, Houston, Tex., a

Y corporation of Texas Application June 6, 1929, Serial No. 368,810

8 Claims. (01.123-198 The invention relates to pistons employed in two-cycle internal combustion engines.

It is an object to provide a structure of pis-' ton of this character which is light and strong and capable of being easily polished and kept clean. I

It is desired to do away with the bafile as ordinarily constructed on the outer end of the piston to deflect the incoming charge of fuel to the outer end of the cylinder. I desire to provide a deflecting surface depressed below the forward end of the piston so as to leave the said end free of projections and thus provide an easy manufacing job and also furnish a piston easily kept free of carbon and similar accumulations.

Another object of the invention is to provide a piston for two cycle internal combustion engines which may be machined all over so that uniform sizes and weights of pistons may be obtained.

In the drawing Fig. 1 is a side view partly in elevation and partly in central longitudinal section of a piston body embodying my invention.

Fig. 2 is a central longitudinal section taken at right angles to the view shown in Fig. 1.

Fig. 3 is a tranverse section on the plane 33 of Fig. 2.

Fig. dis an elevational view of the outer end of the piston.

The body or skirt 1 of my piston is shown of the usual cylindrical form to fit within the cylinder in which it works. The said skirt has circumferential grooves 2 therein to receive piston rings as is common practice. At opposite sides are openings 3, about which are inwardly projecting bearing sleeves 4 integral with the skirt of the piston. The skirt is hollow and said sleeves project inwardly a suitable distance to provide bearings'for a wrist pin, not shown.

The skirt end of the hollow piston body is open, but the outer end is closed by a head 5 which has a smooth and plane outer face 6 except'for arcuate recesses 7 on opposite sides thereof formed by cutting away the said outer head adjacent the periphery of the piston. Said recesses are ofuniform depth. and the inner arcuate walls 8 thereof form bafiles to deflect the incoming and exhaust fuel gases.

The interior face of the head 5 of the piston is reenforced by webs 9. These webs are arranged in parallel intersecting series connected with said head and extending across the said interior face at right angles to each other, with the ends formed or joined to the cylindrical body or skirt 1 of thepiston. These webs form rectangular recesses 10 which appear as the configuration of a waflle and are seenbest in Fig. 3. These webs are provided to reenforce the head of the piston and insure proper distribution of the stresses when the piston is heated in use and expands with the webs or ribs extending ai; right angles 'to each strong and easily constructed. The body is cast or moulded in the proper shape and the outer surface is then easily machined. The recesses '7 .are cut away and the surfaces may then be easily polished to eliminate all rough places where the carbon can gather. This does away with the ordinary bafiles which project from the outer ends of pistons employed in two-cycle internal combustion motors. Such prior pistons are difficult to cast or otherwise form accurately and furthermore they furnish a projection difiicult to machine and which provide a surface upon which carbon easily accumulates, acting to foul the piston.

The baffle provided by the walls -8 of the recesses 7 serve to deflect the liquid or gaseous fuel entering the cylinder in the same manner as does the more common type of baffle but avoids the usual objections to difliculties of manufacture and use.

From the foregoing description it will be apparent that the present piston is simple in its construction and may be readily machined all over to obtain uniformity as to size and weight in quantity production. With pistons for two-cycle enginesl heretofore usedand employing baflies on the'fiead thereof, the'bafiie has usually been cast upon the head. This is a more or less difficult problem as the proper retention of the, core during the casting operation is practically impossible. "Then the bafile projectingirregularly from the hea'dprevents accurate and economical machining of pistons. The result with such prior pistons has been very unsatisfactory and resulted in disuse of two-cycle engines to a considerable extent, because a uniform piston could not be obtained. Where the pistons of an engine are not uniform in size and weight'the engine is unbalanced and a uniform compression in all of the cylinders cannot be obtained. Instances of variation in compression in the different cylinders of as much as five pounds has been known with cast baflie pistons.

It is with the object of eliminating these deiects that I have devised the present piston and lue to its simplicity, am enabled to produce economically and uniformly pistons adapted for use in two-cycle engines.-

What I claim as new is:

1. A piston of cylindrical shape, the inner por tion thereof being hollow, intersecting transverse webs reinforcing the forward end of said piston, and recesses on the outer sides of said forward end, the inner walls of which form baflies.

2. In a piston for internal combustion engines, a skirt, a head therefor, and means adapted to reenforce said head, said means including a plurality of ribs intersectiong each other at right angles and connected at their ends to said skirt whereby expansion of said ribs upon heating will cause a uniform expansion of said piston.

3. A piston including a head anda skirt, and a plurality of uniformly disposed transversely intersecting ribs forming a grid and joining said head and skirt.

4. The combination with a piston having a head and a skirt, of a grid on the underside of the head joined to the skirt and formed of two series of straight intersecting ribs to reenforce said head.

5. A piston of the character described including a skirt, a head, a plurality of transverse intersecting ribs spanning the undersurface of said head, each of saidribs having its ends connected to said skirt, said ribs being adapted to expand said skirt equa'lly'when heated.

6. A piston including ahead and a skirt, a plurality of transverse depending parallel webs spanning the underside of said head, each of said webs having its ends joining said skirt whereby said skirt will be expanded radially in all directions by said webs.

'7. A piston including a head and a skirt, a reenforcing means formed integral with said head and said skirt, said means including two sets of intersecting spaced parallel ribs spanning the distance between the points of connection with said skirt and adapted to expand uniformly against said skirt.

8. A piston including a head and a skirt, a plurality of parallel ribs spanning said head and having their ends joining said skirt, said ribs comprising struts to reenforce said head and cause uniform expansion and contraction of said skirt whereby its true circular form will be maintained during actual use.

. BEN G. PARSONS. 

